Optical transceiver module and duplex fiber optic connector

ABSTRACT

Various embodiments of duplex fiber optic connectors and optical transceiver modules are provided. One embodiment comprises an optical transceiver module comprising: an integrally-formed housing having a duplex front port with a pair of alignment holes for receiving a pair of ferrules from a duplex fiber optic connector, the duplex front port having an upper flexible retaining element and a lower flexible retaining element for retaining the pair of ferrules from the duplex fiber optic connector; an opto-electronic assembly contained within the housing; and an electrical interface extending from the integrally-formed housing.

This application is a divisional application of, and claims the benefitof the priority of, copending U.S. patent application Ser. No.12/040,986, entitled “Optical Transceiver Module and Duplex Fiber OpticConnector,” filed on Mar. 3, 2008, which is hereby incorporated byreference in its entirety.

BACKGROUND

In the area of wire communications, there are electrical and opticalcommunication links between equipment. An electrical link commonlycomprises an electrical transmitter and an electrical receiver that areconnected by metal wire. The electrical transmitter converts informationto an electrical signal and then transmits it over the metal wire whichacts as a transmission medium. The electrical receiver converts thereceived electrical signal back to useful information. An optical linkgenerally comprises an optical transmitter and an optical receivercomponent that are connected by a fiber optic cable. The opticaltransmitter typically comprises a light source, such as, for example, alight-emitting diode (LED), which converts an electrical data signalinto a modulated light signal. This light signal is transmitted throughfiber optic cable and is received by the optical receiver, whichgenerally comprises a light detector, such as, for example, aphotosensor, photodiode, etc. The optical receiver converts the lightsignal back into an electrical data signal.

The housing of an optical transmitter or receiver includes appropriateelectrical pins which provide an electrical input/output (I/O) datainterface with the communications equipment. The front face of thehousing (which comprises a plastic or similar material) includes analignment port for receiving a fiber optic connector to which a fiberoptic cable is terminated. The optical transmitter and receiver areconnected by an optical fiber.

To secure the fiber optic connector within the alignment port, thehousing may also include features for retaining the connector in thealignment port. A typical industrial connector such as Versatile Linkincludes a horizontal C-shaped feature defined by opposing elements thatprotrude from the front face at the alignment port.

The use of fiber optics provides a number of advantages over metalwires. Fiber optic cable allows the transport of data signals overlonger distances. Fiber cables are lighter than metal wires because theyare made of clear glass, polymer, or similar materials. The fiber opticcable is non-conductive and, therefore, protects against electricalshorts and lightning strikes. Optical signals are not degraded byelectromagnetic interference (EMI) and, therefore, may provide bettersignal integrity than metal wires. Optical fiber also provides betterdata security protection because it is much more difficult to tapsignals along a fiber.

In fiber optic applications, the polymer optical fiber (POF) cable ismore cost effective than glass optical fiber cable. It also provideseasy field termination and is less sensitive to dust contamination dueto large fiber core diameter.

SUMMARY

Various embodiments of optical transceiver modules and duplex fiberoptic connectors are provided. One embodiment comprises an opticaltransceiver module. One such module comprises: an integrally-formedhousing having a duplex front port with a pair of alignment holes forreceiving a pair of ferrules from a duplex fiber optic connector, theduplex front port having an upper flexible retaining element and a lowerflexible retaining element for retaining the pair of ferrules from theduplex fiber optic connector; an opto-electronic assembly containedwithin the housing; and an electrical interface extending from theintegrally-formed housing.

Another embodiment comprises a duplex fiber optic connector. One suchconnector comprises: an integrally-formed housing having a top portionand a bottom portion connected via a flexible hinge and defining a pairof channels for receiving a transmitter fiber optic cable and a receiverfiber optic cable at a first end of the integrally-formed housing; apair of ferrules disposed on a second end of the integrally-formedhousing opposite the first end, one ferrule for receiving a first fibercore associated with the transmitter fiber optic cable and the otherferrule for receiving a second fiber core associated with the receiverfiber optic cable; a connector latching element disposed on one of thetop portion and the bottom portion; and a connector orientation key orkeyway disposed on the other of the top portion and the bottom portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagram of one embodiment of an opticaltransceiver module adapted to receive the duplex fiber optic connectorof FIGS. 3-5.

FIG. 2 is a partially exploded view of the optical transceiver module ofFIG. 1.

FIG. 3 is perspective diagram of one embodiment of a duplex fiber opticconnector adapted to be received by the optical transceiver module ofFIGS. 1 & 2.

FIG. 4 illustrates the duplex fiber optic connector of FIG. 3 with thehousing closed.

FIG. 5 is a bottom view of the duplex fiber optic connector of FIGS. 3 &4.

FIG. 6 illustrates the installation of the duplex fiber optic connectorinto the optical transceiver module.

FIG. 7 illustrates the engagement of the duplex fiber optic connectorand the optical transceiver module.

FIG. 8 is a side view that illustrates the engagement of the duplexfiber optic connector and the optical transceiver module.

FIG. 9 a is a side view of an alternative embodiment of an opticaltransceiver module adapted to receive the duplex fiber optic connectorof FIGS. 3-5.

FIG. 9 b is a front view of the optical transceiver module of FIG. 9 a.

FIG. 9 c is a perspective bottom view of the optical transceiver moduleof FIG. 9 c, illustrating optical transceiver mounted withincommunication equipment with electrical I/O interface layout andmounting holes.

DETAILED DESCRIPTION

Various embodiments of a duplex fiber optic connector 100 and anassociated optical transceiver module 200 are described. The opticalcommunication module 200 and the corresponding duplex fiber opticconnector 100 accommodate a transmitter and receiver component to forman optical transceiver module. As described below in more detail, in oneembodiment, the optical transceiver module 200 comprises two generallyC-shaped vertical protrusions that are adapted to hold the duplex fiberoptic connector 100. This configuration reduces the physical footprintof existing modules to untwisted pair (UTP) module size and also sharesthe same layout for the electrical I/O pins. Therefore, the opticaltransceiver module 200 may be conveniently substituted for an electricaltransceiver in, for example, high density electrical network hubs,routers, and switches. This general configuration for the opticaltransceiver module may also enable backwards compatibility with existingSimplex Versatile Link (VL) connectors that are commonly used in, forexample, industrial fiber optic links. Furthermore, the duplex fiberoptic connector 100 and the optical transceiver module 200 support animproved connector latching feature that improves the retention forcerobustness, is less prone to breakage as compared to existing modulesand connectors, such as the current range of VL connectors, and alsooffers a connector orientation feature for ease of insertion.

FIGS. 1 & 2 illustrate an embodiment of the optical transceiver module200 which is configured to receive the duplex fiber optic connector 100.The optical transceiver module 200 is further configured to support aconnector latching feature and a connector orientation feature, asdescribed below in more detail. Referring to FIGS. 1 and 2, the opticaltransceiver module 200 comprises a housing 202 having a duplex frontport 208 and an electro-optical assembly 210. The electro-opticalassembly 210 includes an optical transmitter and an optical receiver. Asknown in the art, the optical transmitter generally comprises thecomponents for generating an optical signal (e.g., a light source, suchas a light-emitting diode (LED), and focus elements), and the opticalreceiver generally comprises the components for receiving an opticalsignal (e.g., a photodetector or photosensor). The optical transceivermodule 200 has electrical pins 214 to provide the electrical interfaceto a communication management system, such as, for example, a networkhub, a router, a switch, or any other data communication device orequipment. To provide support when installed into the communicationequipment, the optical transceiver module 200 may include supportpedestals 216.

The housing 202 may comprise any suitable material. In one embodiment,the housing 202 may be integrally formed from a plastic or similarmaterial using, for example, injection molding or other manufacturingtechniques. In other embodiments, the housing 202 may comprise separatecomponents made of other materials, which are joined together to formthe optical transceiver module 200, as illustrated in FIG. 2. Thehousing 202 may be protected by a metal shell 212 that fits over thehousing 202, while providing functional access to the duplex front port208 and pins 214.

FIGS. 9A-9C illustrate another embodiment of the optical transceivermodule 200. In this embodiment, the metal shell 212 with more than oneprotrusion serves as grounding connectors 230 for the housing 202, whichis connected to equipment, such as, a printed circuit board (PCB) groundplane 232 to reduce EMI emission. Flexible metal fingers 234 may belocated, for example, on the front side of the metal shell 212. Theflexible metal fingers 234 make contact with communication equipmentmetal housing 236 to further improve electromagnetic interfaceshielding.

The duplex front port 208 comprises a pair of ferrule alignment holes204 and 206. Alignment hole 204 is associated with the opticaltransmitter and the alignment hole 206 is associated with the opticalreceiver. The duplex front port 208 is adapted to receive and retain theduplex fiber optic connector 100. The duplex front port 208 includes apair of flexible retaining elements for retaining the duplex fiber opticconnector 100. In the embodiment illustrated in FIGS. 1 and 2, an upperflexible retaining element 218 and a lower flexible retaining element220 extend outward from the duplex front port 208. The flexibleretaining elements 218 and 220 may be slightly angled toward the ferrulealignment holes 204 and 206. In this manner, the flexible retainingelements may clamp down on the duplex fiber optic connector 100 when theferrules 114 and 116 are inserted into the alignment holes 204 and 206,as described below. The slot 222 and cut-out 224 allow the left andright side of the flexible retaining elements 218 and 220 to deflectindependently. It should be appreciated that, in certain embodiments,this feature may enable flexible retaining elements 218 and 220 to clampdown, for example, two simplex Versatile Link connectors with varyingferrule diameters.

As illustrated in FIG. 9 c, in certain embodiments, the opticaltransceiver module 200 may be configured with the same electrical I/Ointerface layout as a conventional unshielded twisted pair (UTP)electrical transceiver module, with two flexible snap-fit pedestals 216.The snap-fit pedestals 216 may serve two general functions: (1) tosupport the module and (2) to prevent module dislodges from theequipment PCB before soldering. It should be further appreciated thatthe the duplex fiber optic connector 100 may be configured with the sameconnector physical size as a conventional UTP connector. The reducedexternal footprint may offer a space savings advantage for fibercommunication solutions in, for example, consumer and industrialapplications where the spacing between transceiver modules becomescritical (e.g., in network hubs, routers and switches). Furthermore,this may allow the optical transceiver module 200 to be easilyincorporated into existing UTP designs.

The duplex fiber optic connector 100 comprises a connector housing 102having a top portion 104 and a bottom portion 106. The top portion 104and the bottom portion 106 may be joined at adjacent edges by a flexiblehinge 108, which enables the connector housing 102 to be opened (FIG. 3)and closed (FIGS. 4 & 5) and, thereby, provide access to the interior ofthe connector housing 102 for installing a pair of fiber optic cables(i.e., a transmitter fiber optic cable 110 and a receiver fiber opticcable 112). In one embodiment, to provide a low cost connector, theconnector housing 102 may be integrally formed from a plastic or similarmaterial using, for example, injection molding or other manufacturingtechniques. In other embodiments, the connector housing 102 may compriseseparate components made of other materials, which are joined togetherto form the connector housing 102.

One end of the connector housing 102 supports ferrules 114 and 116, andthe opposing end receives the transmitter fiber optic cable 110 and thereceiver fiber optic cable 112. Ferrule 114 receives a fiber core 118associated with the transmitter fiber optic cable 110, and the ferrule116 receives a fiber core 118 associated with the receiver fiber opticcable 112. Ferrules 114 and 116 provide the structure for preciselyaligning the corresponding fiber cores 118 with a transmitter port and areceiver port disposed on a front face of the optical transceiver module200. In this manner, optical signals may be carried along transmitterfiber optic cable 110 and ferrule 114, and optical signals may becarried along receiver fiber optic cable 112 and ferrule 116. Theinstallation of the duplex fiber optic connector 100 into the opticaltransceiver module 200 is described in more detail below.

FIG. 3 shows a partially exploded view of the duplex fiber opticconnector 100 with the connector housing 102 open to expose the interiorof the duplex fiber optic connector 100. In the embodiment illustratedin FIG. 3, a pair of channels 120 is formed on both the top portion 104and the bottom portion 106 of the connector housing 102 for receivingfiber cores 118. The pairs of channels 120 are aligned such that thetransmitter fiber optic cable 110 and the receiver fiber optic cable 112are securely positioned within the channels 120 and the fiber cores areprecisely aligned with the ferrules 114 and 116. Cablealignment/restraining elements 122 may be positioned along the channels120 to guide and hold the fiber optic cables 110 and 112 duringinstallation, or further support or align the fiber core 118 or thefiber optic cables 110 and 112.

As further illustrated in FIG. 3, the fiber optic cables 110 and 112enter the connector housing 102 at the end opposite ferrules 114 and116. Cables 110 and 112 comprise a predefined length of fiber core 118.The length of core exposed may be based on the physical dimensions ofthe interior of the duplex fiber optic connector 100. For example, thelength of fiber core 118 may be based on the length of core to bereceived in ferrules 114 and 116. During installation, the fiber core118 may be exposed by stripping off the fiber cable jacket with, forexample, a fiber stripping tool. In one embodiment, the fiber opticcables 110 and 112 may comprise a plastic or acrylic optical fiber with,for example, a general-purpose resin as the core material and a polymermaterial for the cladding material. It should be appreciated, however,that alternative materials may be used for the core, cladding, or othercomponents. Slight protrusions which are sloping forward and backwardaway from the protrusion can be found behind ferrule 114, 116 and whichact as connector retention features 140 (FIG. 8). The flexible retainingelements 218, 220 will hold the retention features 140 in place withresultant force 240 once the connector is fully inserted into thetransceiver module. The resultant force 240 is translated into verticalforce component 242 and horizontal force component 244 which are actingon the connector. The horizontal force component 244 pushes theconnector which in turn preloads ferrule 114, 116 end faces to mate withtransceiver optical reference 226 as demonstrated on FIG. 7.

The fiber optic cables 110 and 112 may include a strain relief boot 124.The strain relief boots 124 may cover the fiber optic cable at or nearthe point at which the cable enters the connector housing 102. Thestrain relief boots 124 may be formed on the fiber optic cable or,alternatively, may be inserted over the fiber cables 110 and 112 duringinstallation. To assist in the installation process and support theretention of the fiber optic cables 110 and 112 within the connectorhousing 102, the strain relief boots 124 may incorporate a ring 126which engages with a corresponding recess in the top portion 104 or thebottom portion 106 of the housing (FIG. 3). During installation, thestrain relief boots 124 may be placed onto the bottom portion 106 of theconnector housing 102 with the ring 126 resting in the recess and thefiber cores 118 inserted into the corresponding ferrules. The fiber core118 extends along the length of the corresponding ferrule and ends at ornear a ferrule front face 119. The cable alignment/restraining elements122 restrain the fiber optic cables in place when the top portion 104and the bottom portion 106 are closed onto each other.

With the fiber optic cables 110 and 112 in place within the connectorhousing 102, the top portion 104 and the bottom portion 106 may beclamped together via a latching mechanism. As illustrated in FIG. 3, oneor more flexible latching elements 128 may be placed on the underside ofthe top portion 104. One or more corresponding latch holding features130 may be placed on the bottom portion 106. The flexible latchingelements 128 and the latch holding features 130 may be formed integrallywith the connector housing 102 or otherwise attached to the connectorhousing 102. The flexible latching elements 128 are positioned to latchonto the latch holding features 130 when the top portion 104 is closedonto the bottom portion 106. The flexible latching elements 128 may bedepressed to release the latching mechanism and enable the connectorhousing 102 to be opened.

The duplex fiber optic connector 100 may include a latching feature forreleasable latching the connector to the optical transceiver module 200,and an orientation feature for properly orienting the connector relativeto the optical transceiver module 200. The orientation feature ensuresthat the duplex fiber optic connector 100 is inserted into the opticaltransceiver module 200 with the transmitter and receiver cables 110 and112 linked to the appropriate transmitter and receiver ports. Thelatching feature provides a convenient mechanism for releasable securingthe duplex fiber optic connector 100 to the optical transceiver module.

Having described the general components of the duplex fiber opticconnector 100 and the optical transceiver module 200, the orientationand latching features mentioned above will now be described in moredetails. To enable the latching feature, in one embodiment asillustrated in FIG. 4, a latch element 132 is positioned on the topportion 104 of the duplex fiber optic connector 100. The latch elementis designed to be lower than top potion 104 of connector housing andstrategically placed in between ferrules 114, 116 which providesthree-way protections against damage from external element. The latchelement comprises a flexible base element having a latch 132. Theflexible base element may be configured to vertically flex relative tothe connector housing 102 such that the latch 132 is depressed as theduplex fiber optic connector 100 is inserted into the opticaltransceiver module 200. The latch 132 may include an angled frontsurface which engages the upper flexible retaining element 218 as theduplex fiber optic connector is inserted.

As illustrated in FIGS. 1 & 2, the upper flexible retaining element 218on the optical transceiver module 200 may include a suitably-shapedcut-out 222 to receive the latch 132. FIG. 7 shows the proper engagementof the latch 132 and the cut-out 222 to retain the duplex fiber opticconnector 100 in the optical transceiver module 200. It should beappreciated that the latch 132 and the cut-out 222 may be shaped invarious ways to implement the latching function. In one embodiment, thecut-out 222 is a triangular-shaped cut-out, although key and keywayarrangements may be employed. It should be further appreciated that thelocation of the latching element and the cut-out 222 may be varied.Furthermore, in alternative embodiments, the latch element may furthercomprise a release tab 134 disposed on the flexible base element thatextends above the upper surface of the connector housing 102 forreleasing the latch 132 from the cut-out 222.

The orientation feature is provided, in one embodiment, via anorientation key 136 which locates on the connector housing 102. In theembodiment illustrated in FIG. 2, the orientation key 136 is disposed onthe bottom surface of the bottom portion 106 of the connector housing102. As illustrated in FIG. 2, the bottom flexible retaining element 220of the optical transceiver module 200 may include a slot 224 forengaging with the orientation key 136. In this manner, the opticaltransceiver module 200 will only receive the duplex fiber opticconnector 100 when the orientation key 136 is properly oriented with theslot 224. This will prevent the duplex fiber optic connector from beingimproperly inserted with the ferrules 114 and 116 reversed relative tothe alignment holes 204 and 206. It should be appreciated that theorientation key 136 and the slot 224 may be shaped in various ways toaccommodate a key-to-keyway engagement. It should be further appreciatedthat the number and location of these elements may be varied.Furthermore, in alternative embodiments, the orientation key 136 may bepositioned on the optical transceiver module 200 and the slot 224 may beplaced on the duplex fiber optic connector 100.

FIG. 7 generally illustrates the manner in which the duplex fiber opticconnector 100 may be inserted into the optical transceiver module 200.The ferrules 116 and 114 may slide along the alignment holes 204 and206, respectively, and stop when the front face 119 comes in contactwith an optical reference element (e.g., surface 226). As the ferrules114 and 116 are received in the alignment holes 204 and 206, the latch132 engages the cut-out 222 and the orientation key 136 engages the slot224.

It should be noted that this disclosure has been presented withreference to one or more exemplary or described embodiments for thepurpose of demonstrating the principles and concepts of the invention.The invention is not limited to these embodiments. As will be understoodby persons skilled in the art, in view of the description providedherein, many variations may be made to the embodiments described hereinand all such variations are within the scope of the invention.

1. An optical connector assembly comprising: a duplex fiber opticconnector comprising an integrally-formed connector housing comprising:a top portion and a bottom portion connected via a flexible hinge anddefining a pair of channels for receiving a transmitter fiber opticcable and a receiver fiber optic cable at a first end of theintegrally-formed connector housing; and a pair of ferrules disposed ona second end of the integrally-formed connector housing opposite thefirst end, one ferrule for receiving a first fiber core associated withthe transmitter fiber optic cable and the other ferrule for receiving asecond fiber core associated with the receiver fiber optic cable; and anoptical transceiver module comprising: an integrally-formed transceiverhousing having opposing top and bottom surfaces and a front surfaceperpendicular to the top and bottom surfaces, the front surface having aduplex front port with a pair of alignment holes for receiving the pairof ferrules from the duplex fiber optic connector in a directionparallel to the top and bottom surfaces, the duplex front port having anupper flexible retaining element positioned on the front surfaceadjacent the top surface and a lower flexible retaining elementpositioned on the front surface adjacent the bottom surface, the upperand lower flexible retaining elements adapted to vertically flexrelative to the top and bottom surfaces and thereby retain the pair offerrules; an opto-electronic assembly contained within the transceiverhousing; and an electrical interface positioned on and extending awayfrom the bottom surface of the transceiver housing.
 2. The opticalconnector assembly of claim 1, wherein the transceiver housing and theconnector housing comprise injection-molded plastic.
 3. The opticalconnector assembly of claim 1, wherein one of the connector housing andthe transceiver housing comprises an orientation key and the othercomprises an orientation keyway.
 4. The optical connector assembly ofclaim 3, wherein one of the connector housing and the transceiverhousing further comprises a latch and the other comprises a cut-out forreceiving the latch.
 5. A duplex fiber optic connector comprising: anintegrally-formed housing having a top portion and a bottom portionconnected via a flexible hinge and defining a pair of channels forreceiving a transmitter fiber optic cable and a receiver fiber opticcable at a first end of the integrally-formed housing; a pair offerrules disposed on a second end of the integrally-formed housingopposite the first end, one ferrule for receiving a first fiber coreassociated with the transmitter fiber optic cable and the other ferrulefor receiving a second fiber core associated with the receiver fiberoptic cable; a connector latching element disposed on one of the topportion and the bottom portion; and a connector orientation key orkeyway disposed on the other of the top portion and the bottom portion;wherein the top portion and the bottom portion have an upwardlyextending protrusion for engaging with upper and lower flexibleretaining elements, respectively, of an optical transceiver module andapplying a horizontal and vertical retention force to the integrallyformed housing.
 6. The duplex fiber optic connector of claim 5, whereinthe housing comprises an injection-molded plastic material.
 7. Theduplex fiber optic connector of claim 5, wherein the connector latchingelement comprises a flexible base element.
 8. The duplex fiber opticconnector of claim 5, wherein one of the top portion and the bottomportion includes at least one latch element, and the other of the topportion and the bottom portion includes at least one recess forreceiving the latch element.